Method for carrying out a shift during hybrid operation in a parallel hybrid vehicle

Abstract

A method of carrying out a shift with traction force interruption during hybrid operation in a parallel hybrid vehicle having an automated transmission. The method comprises the steps of maintaining the coupling between the internal combustion engine ( 1 ) and the electric machine ( 2 ), eliminating the load before disengaging the old gear, and synchronizing to the new gear by the operation of the electric machine ( 2 ).

1. A method of carrying out a shift with traction force interruption during hybrid operation in a parallel hybrid vehicle having an automated transmission and a single electric machine connected between an internal combustion engine and an input shaft of the automated transmission, the method comprising the steps of:
 maintaining a coupling between the internal combustion engine ( 1 ) and the electric machine ( 2 ); 
 one of (a) operating the internal combustion engine at a constant torque and (b) adjusting a torque from the internal combustion engine when the torque from the internal combustion engine exceeds a threshold value, and 
 operating the electric machine to compensate for torque from the internal combustion engine to eliminate a load on the input shaft of the automated transmission; and 
 disengaging an old transmission gear and synchronizing to a new transmission gear. 
 
     
     
       2. The method of carrying out a shift with traction force interruption according to  claim 1 , further comprising the step of:
 adjusting the torque from the internal combustion engine ( 1 ), or when an energy accumulator of the vehicle would become overcharged due to the torque compensation by the electric machine ( 2 ). 
 
     
     
       3. The method of carrying out a shift with traction force interruption, according to  claim 1 , further comprising the step of disengaging the old transmission gear, after the load on the input shaft of the automated transmission is eliminated, and then synchronizing the new transmission gear by adjusting a speed of the electric machine ( 2 ) to a synchronous speed of the new transmission gear. 
     
     
       4. The method of carrying out a shift with traction force interruption, according to  claim 3 , further comprising the step of adjusting the speed of the electric machine ( 2 ) by switching the electric machine ( 2 ) from a torque-controlled mode to a speed regulation mode in which the speed of the electric machine ( 2 ) is adjusted, with the torque from the internal combustion engine being a pilot torque for a speed regulator of the electric machine ( 2 ). 
     
     
       5. The method of carrying out a shift with traction force interruption, according to  claim 4 , further comprising the step of engaging the new transmission gear after the synchronization to the new transmission gear; and
 increasing the load on the input shaft of the automated transmission, according to a torque which is desired by the driver, and returning the electric machine to the torque-controlled mode for increasing the load build-up on the input shaft of the automated transmission, when the speed of the electric motor was adjusted to the synchronous speed of the new transmission gear in the speed regulation mode. 
 
     
     
       6. The method of carrying out a shift with traction force interruption, according to  claim 5 , comprising the step of adjusting the electric machine ( 2 ) and the internal combustion engine ( 1 ) to torques determined by a separate torque distribution strategy for the load build-up on the input shaft of the automated transmission. 
     
     
       7. The method of carrying out a shift with traction force interruption, according to  claim 1 , further comprising the step of operating the electric machine as a generator during a shift.